Alkaryl sulfonate detergents



Patented Oct. 28, 1952 ALKARYL SULFONATE DETERGENTS Kenneth M. Thompson,Aidan, Pa., assignor to The Atlantic Refining Company, Philadelphia,Pa", a corporation of Pennsylvania No Drawing. Application January 27,1950,

Serial No. 140,949

The present invention relates to alkylated aryl sulfonatedetergents,'and relates more particu-' larly to the lowering of thecloud point and the improvement in color of aqueous solutions ofalkylated aryl sulfonates.

j It has been common practice heretofore to manufacture and sellconcentrated aqueous solutions of alkylated aryl sulfonates, the alkylgroup of which contains from 9 to 15 carbon atoms, and preferably about12 carbon atoms., These solutions usually contain inorganic salts suchas sulfates of the alkali metals in minor amounts, which salts wereproduced in the course of manufacture of the sulfonates and were notremoved from the final product. Depending upon the molecular weight ofthe alkyl group and the concentration of the sulfonates in the solution,the' solubility and hence the cloud point varies. With increase inmolecular weight or with concentration, the cloud point likewiseincreases. 'Since it is desirable to ship the sulfonate solutions in ashigh a concentration as is possible while retaining homogeneity within areasonable temperature range, handling difliculties occur when thetemperature of the solution drops below the .cloud point, particularlyover an extendedperiod of time. At temperatures below the cloud point,as determined by the A. S. T. M. MethodDQ'I-'l, the sulfonates tend toprecipitate from aqueous solution, thus giving rise to non-uniformity ofthe solution. This is particularly troublesome in handling sulfonatesolutions in bulk, i. e., transportation in tank cars or storage inunheated tanks.

In accordance with the present invention there is provided a method notonly for overcoming the above difiioulty, but also for improving thecolor or the sulfonate products; Such method comprises adding to thealkylated aromatic hydrocarbon or hydrocarbon mixture in which the alkylgroup contains from 9 to 15 carbon atoms, a minor amount of xylene, i.e., from 5% to 25% by volume, subjecting the mixture to sulfonation, andrecovering the resulting mixed sulfonic acids, or their correspondingalkali metal, ammonium, or amine salts.

The xylene to be employed may be one or a mixture of the isomericxylenes, commercially available xylenes in which the meta isomerpredominates being preferred for economic reasons; The alkylatedaromatic hydrocarbons containing known methods.

5 Claims. 7 (01. 252-461) from 9 to carbon atoms in the alkyl group maybe produced by any one of a number of well- The aromatic hydrocarbonused is preferably benzene, although toluene, xylene, cumene,naphthalene, and the lower alkyl naphthalenes are also suitable foralkylation. Such alkylation may be accomplished by treating an excess ofan aromatic hydrocarbon such as benzene with a halogenated aliphatichydrocarbon of 9 to 15 carbon atoms in the presence of a suitablealkylation catalyst of the Frie'del-Crafts 2,387,572; and 2,469,378.

The alkylated benzene may also be produced by alkylating benzene with analcohol or mono olefin of 9 to 15 carbon atoms, using sulfuric acidcatalyst, or Friedel-Crafts catalysts as the case may be.

A further method for producing the alkyl benzene or mixture of alkylbenzenes having 9 to 15 carbons in the alkyl group is to polymerize anolefin such as propylene, or a gas stream con- Y taining propylene, witha supported phosphoric acid catalyst at elevated temperature andpressure, for example, 300 F. to 600 F. and 200 to 600 lbs/sq. in.pressure, thereby obtaining a mixture of 'propylenepolymers containingfrom 6 to 18 or more carbon atoms per molecule, and then fractionallydistilling the mixture to separate a polymer fraction of desired boilingrange or carbon atom content. Such fraction may comprisepropylenepolymersof from 9 to 15 carbon atoms,,

or from 9 to 12 carbon atoms, or from 12 to 15 carbon atoms. Mostdesirable is a close out fraction averaging about12 carbon atoms.Benzene or other aromatic hydrocarbon is'then alkylated with thepropylene polymer fraction in the presence of a'l riedel-Craftscataly's't such as AlCla, ZnClz, l-IF, or with a sulfuric acidcatalystto obtainan alkyl benzene or mixture of alkyl benzenes, which, ifnecessary, may be fractionally distilled to yield the, desiredsulfonation stock.

Alkylation processes of this type are disclosed in United States'PatentsNos. 1,992,160; 2,232,118; 2,430,673;'2,477,382; and 2,477,383.

"Regardless of its method of production, the

alkyl benzene having an alkyl group of from 9 to 15 carbon atoms, oramixture of alkyl benzene's withinthis'range; and preferably a mixturehaving an average of 12 carbons in the alkyl group, is then mixed with5% to 25% by volume of xylene. Such mixture is then subjected tosulfonation with an agent such as sulfuric acid of 98% to 100%concentration, preferably at 150 F.160 FL, using about 1 volume of acidper volume of the alkyl benzene-xylene mixture. After the sulfonation iscompleted, the reaction mixture is diluted with a solvent such asbenzene, and the spent sulfuric acid is settled out. the alkyl benzenesulfonic acids remaining in solution in the immiscible benzene layer.The benzene solution of sulfonic acids is then extracted with water oraqueous alcohol to dissolve and remove the sulfonic acids. The water oraqueous alcohol solution is separated from the benzene, neutralized witha suitable base such as aqueous sodium hydroxide, and the resultingsodium sulfonate solution is evaporated to remove water, or aqueousalcohol, and traces of benzene to give an aqueous solution of sulfonatesof 30% to 50% concentration, and containing usually about to ofinorganic salt, i. e., sodium sulfate. The sodium sulfonates comprise amixture of the higher alkyl benzene sulfonates having from 9 to 15, andpreferably about 12 carbon atoms in the alkyl group, together with thexylene sulfonate. higher alkyl benzenes and from 5% to 25% of xylene, ithas been found that not only is the solubility of the ultimate sulfonateproduct substantially increased at high concentrations, but also thecolor of the product is improved. On the other hand, it has been foundthat when the higher alkyl benzenes are separately sulfonated, and thexylene is Separately sulfonated, and the resulting products are mixed,the solubility of the resultant product, as measured by cloud point, isnot as great, and no color improvement is obtained. Moreover, theproduct resulting from the joint sulfonation of the mixture of higheralkyl benzenes and xylene shows no decrease in deters gency for W001 orcotton, and no decrease in foam, calcium ion tolerance, or increase inwet-, ting time and surface tension over that normally obtained from thehigher alkyl benzene sulfonates, per se. In other words, the jointsulfonation of the higher alkyl benzenes and from 5% to 25% of xyleneyields a product of improved solubility and color, and with nosubstantial change in the other properties common to the higher alkylbenzene sulfonates.

The present invention may be further illus. trated by the followingexamples, which, however, are not to be construed as limiting the scopethereof.

1. A gas stream comprising about 80% propylene, with minor amounts ofpropane, ethane, ethylene, and methane was contacted with a catalystconsisting of phosphoric acid impregnated on kieselguhr at 500 F. and400 lbs/sq. in. pressure, at a rate of 0.1 lb. mole of propylene per lb.of catalyst per hour. ture of propylene polymers containing from 6 to 15carbon atoms was fractionally distilled to remove an overhead fractioncomprising primarily propylene dimers and trimers. The distillationresidue or bottoms boiling between 340 F. and 550 F. and comprisingmainly propylene tetramers with minor amounts of trimers and pentamers,was admixed with 6 molar equivalents of benzene, and the mixture treatedwith AlCh catalyst at 150 F.-160 F. to effect alkylation of the benzenewith the propylene polymers. After removal of spent catalyst andtreatment of the By sulfonating a mixture of The resulting mixcrudealkylate with caustic soda solution and with water, the crude alkylatewas fractionally distilled to remove excess benzene and low boilingalkyl benzenes. The distillate residue or bottoms boiling between 450 F.and 680 F. and comprising for the most part a mixture of dodecylbenzenes, with minor amounts of lower and higher alkyl benzenes (nonyl,decyl, and pentadecyl benzenes) constituted the basic material for thepreparation of the sulfonate detergents. A portion of basic material, i.e., alkyl benzenes averaging 12 carbons in the alkyl group, was setaside for the production of the corresponding sulfonate, while theremainder was mixed with varying percentages of xylene, i. e., 5%, 10%,15%, and-20%, for the production of the mixed sulfonates.

In each case, ,1 volume of the hydrocarbons to be sulfonated wascontacted with 1 volume of 98% concentration sulfuric acid at F.- F. for35 minutes-to effect sulfonation. The sulfonat-ion reaction mixture wasthen diluted with 6 volumes pf benzene and permitted to settle andstratify into an upper layer comprising benzene containing thehydrocarbon sulfonic acids, and minor amounts of' unsulfonatedhydrocarbons and entrained sulfuric acid. The lower layer consistedessentially of spent sulfuric acid, together with traces of benzene andunsulfonated hydrocarbon. After separation of the respective layers, thebenzene solution of hydrocarbonsulfonic acids was mixed with'3 volumesof 40% methanol, and the mixture permitted to settle. The lower layercomprising aqueous methanol and the extracted sulfonic acids and tracesof sulfuric acid was separated from, the upper benzene layer containingunsulfonated, hydrocarbon. The aqueous methanol solution was thenneutralized with 25% concentration aqueous sodium hydroxide to a pH ofabout 3, washed with 3 volumes of benzen to remove traces ofunsulfonated hydrocarbon, and the washed, partially neutralized aqueousmethanol solution was finally neutralized with additional aqueous sodiumhydroxide to a pH of 7 or slightly higher. The neutral solution ofsulfonates was evaporated to remove water, methanol, and traces ofbenzene, giving an aqueous solution containing about 35%. of solids(85%. ofwhich was active sulfonate and 15% was inorganic salt, mostlysodium sulfate).

In order to show the effect of separately sulfonating xylene and thenadding. the resulting sodium xylene sulfonate to the separately preparedbasic material, 1. e., sodium dodecyl' benzene sulfonate, a quantity ofxylene was sulfonated by conventional procedure and the sodium xylenesulfonate was added to give the equivalent of 5%, 10%, 15%, and 20%based upon 7 the dodecyl benzene sulfonate. The results with respect tocloud point and color are given in the following tables, the totalsolids concentration in the aqueous sulfonate solutions. being. 35% byweight.

Cloud Point of Solution, F.

Vol. PercentXylene- Y mint ssl i rfi ti n and-addition Color of SolutionSeparate sulfona- Joint sulfonation tion and addition Vol. PercentXylene Lumino- NPA meter It is to be noted that in the Luminometerscale, color decreases with increase in numerical value, whereas in theNPA scale, color decreases with decrease in numerical value. From theabove data it is apparent that joint sulfonation is superior to separatesulfonation and addition, both with respect to decrease in cloud point(or increase in solubility) and improvement in color. This efiect iseven more noticeable with progressive increase in the solidsconcentration (sulfonate) from 35% to 50% by weight.

2. To a propylene polymer alkylated benzene having an average alkylchain length of about 12 carbon atoms was added 15% by volume ofcommercial xylene, the mixture was sulfonated with 98% sulfuric acid,and the sodium sulfonates were recovered as an aqueous concentratecontaining 55% solids. The concentrate was then diluted with water tosuccessively lower concentrations and the cloud points were determined.The results are tabulated below. Of the solids content, active sodiumsulfonate constituted 88.1% and inorganic salts 11.9%.

Percent Solids llfoint,

In lieu of xylene or mixtures of the xylenes, there may be employedethyl benzene having the same molecular weight and the same number ofalkyl carbon atoms. With ethyl benzene in amounts of to 25% by volume,much the same results are obtained as with xylene with respect to thelowering of cloud point of the higher alkyl aromatic sulfonates.

The detergents of the present invention may be marketed in the form ofconcentrated aqueous solutions containing from to 50% or more of solids.These solutions may be spray dried or drum dried to give soliddetergents, or may be mixed with various amounts of alkali metalsulfates, phosphates, polyphosphates, silicates, or other materials andreduced to dry solids, if desired.

I claim:

ofk-afmono-alkylated aryl: hydrocarbon in which theialkyl: groupcontains'from 9 to' 15 carbonat'o'm'sand'. a quantity of an alkylatedaryl hydrocarbon from'the groupconsisting of xylene and ethylbenzenefisuch'zthat vupon sulfonation and neutralization of the mixture,the salt of the sulfonicacid 'derivedfrom the last-mentioned alkylatedarylhydrocarbon will constitute between 5% and 25% of the total saltsofthe sulfonic acids;and recover ing -the resulting sulfonic compoundsfrom the sulfonation mixture.

2. A detergent comprising an aqueous solution of water soluble salts ofalkylated aryl sulfonic acids and inorganic salts, the water solublesalts of the alkylated aryl sulfonic acids constituting a mixture of 95%to 75% of a water soluble salt of a mono-alkylated aryl sulfonic acid inwhich the alkyl group contains from 9 to 15 carbon atoms and 5% to 25%of a water soluble salt of an alkylated aryl sulfonic acid from thegroup consisting of salts of xylene sulfonic acid and salts of ethylbenzene sulfonic acid, said water soluble salts being prepared bysubjecting to the action of a sulfonating agent a mixture of amono-alkylated aryl hydrocarbon in which the alkyl group contains from 9to 15 carbon atoms and a quantity of an alkylated aryl hydrocarbon fromthe group consisting of xylene and ethyl benzene, such that uponsulfonation and neutralization of the mixture, the salt of the sulfonicacid derived from the last-mentioned alkylated aryl hydrocarbon willconstitute between 5% and 25% of the total salts of the sulfonic acids,and recovering the resulting sulfonic compounds from the sulfonationmixture.

3. A detergent composition in which the active ingredients comprise amixture of 95% to 75% of a water soluble salt of a mono-alkylatedbenzene sulfonic acid in which the alkyl group contains from 9 to 15carbon atoms and 5% to 25% of a water soluble salt of xylene sulfonicacid, said water soluble salts being prepared by subjecting to theaction of'a sulfonating agent a mixture of a mono-alkylated benzenehydrocarbon in which the alkyl group contains from 9 to 15 carbon atoms,and a quantity of xylene such that upon sulfonation and neutralizationof the mixture the l. A detergent in which the active ingredientscomprise a mixture of 95% to of a water soluble salt of a mono-alkylatedaryl sulfonic acid in which the alkyl group contains from 9 to 15 carbonatoms and 5% to 25% of a water soluble F to the action of a sulfonatingagent a mixture 75 salts being prepared by subjecting to salt of thexylene sulfonic acid will constitute between 5% and 25% of the totalsalts of the sulfonic acids, and recovering the resulting sulfoniccompounds from the sulfonation mixture.

4. A. detergent composition in which the active ingredients comprise amixture of to 75% of a water soluble salt of a mono-alkylated benzenesulfonic acid in which the alkyl group contains from 9 to 15 carbonatoms and 5% to 25%,of a water soluble salt of ethyl benzene sulfonicacid, said water soluble salts being prepared by subjecting to theaction of a sulfonating agent a mixture of a mono-alkylated benzenehydrocarbon in which the alkyl group contains from 9 to 15 carbon atoms,and a quantity of ethyl benzene such that upon sulfonation andneutralization of the mixture the salt of the ethyl benzene sulfonicacid will constitute between 5% and 25% of the total salts of thesulfonic acids, and recovering the resulting sulfonic compounds from thesulfonation mixture.

5. A detergent composition in which the active ingredients comprise amixture of 95% to 75%01. water soluble salts of mono-alkylated benzenesulfonic acids in which the alkyl groups averag 12 carbon atoms, and 5%to 25% of a water solu ble salt of xylene sulfonic acid, said watersoluble gill-2847; 7 of a'sul-fonatmg' agent a mixhlre of mono alkybREFERENCES CITED med benzene hydrocarbons in which alkyl The followingreferences are of record in the groups average 12 carb'on' atoms, and a;quantity of this patent: of xylene such that upon -sulfonailon andnewtral-izatidn of the mixture, the salt 01 thexylen'e 5 UNITED STATESPATENTS sulfoniiz acid will constitute between 5% and Number Name Date25% of the total salts of the sulfonic acids, and 1,944,367 Pott Jan.23, 1934 recovering the resulting sulfonic'compaunds from 2,161,174-Kyriqles June 2, 1939 the sul-fonation mixturea 2,232,117 gyrides Feb.18, 1941 THONIPSON. 10 2,298,696 Harris Oct. 13, 1942

1. A DETERGENT IN WHICH THE ACTIVE INGREDIENTS COMPRISE A MIXTURE OF 95%TO 75% OF A WATER SOLUBLE SALT OF A MONO-ALKYLATED ARYL SULFONIC ACID INWHICH THE ALKY GROUP CONTAINS FROM 9 TO 15 CARBON ATOMS AND 5% TO 25% OFA WATER SOLUBLE SALT OF AN ALKYLATED ARYL SULFONIC ACID FROM THE GROUPCONSISTING OF SALTS OF XYLENE SULFONIC ACID AND SALTS OF ETHYL BENZENESULFONIC ACID, SAID WATER SOLUBLE SALTS BEING PREPARED BY SUBJECTING TOTHE ACTION OF A SULFONATING AGENT A MIXTURE OF A MONO-ALKYLATED ARYLHYDROCARBON IN WHICH THE ALKYL GROUP CONTAINS FROM 9 TO 15 CARBON ATOMSAND A QUANTITY OF AN ALKYLATED ARYL HYDROCARBON FROM THE GROUPCONSISTING OF XYLENE AND ETHYL BENZENE, SUCH THAT UPON SULFONATION ANDNEUTRALIZING OF THE MIXTURE, THE SALT OF THE SULFONIC ACID DERIVED FROMTHE LAST-MENTIONED ALKYLATED ARYL HYDROCARBON WILL CONSTITUTE BETWEEN 5%AND 25% OF THE TOTAL SALTS OF THE SULFONIC ACIDS, AND RECOVERING THERESULTING SULFONIC COMPOUNDS FROM THE SULFONATION MIXTURE.